Organic eletroluminescent element including polyester electronic material and display device including the same

ABSTRACT

An organic electroluminescent element includes a pair of electrodes formed of a positive electrode and a negative electrode, with at least one of the electrodes being transparent or semi-transparent, and one or more organic compound layers interposed between the pair of electrodes, with at least one layer containing one or more charge transporting polyesters represented by the following formula (I), wherein A 1  represents at least one selected from structures represented by the following formula (II), and X represents a group represented by the following formula (III):

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based on and claims priority under 35 USC 119 fromJapanese Patent Application No. 2011-168827 filed Aug. 1, 2011.

BACKGROUND

1. Technical Field

The present invention relates to an organic electroluminescent elementand a display medium.

2. Related Art

Electroluminescent elements are self-luminescent, all-solid elements.Research on electroluminescent elements using organic compounds has beenstarted initially by using single crystals of anthracene or the like.

The light emission of these elements is a phenomenon in which, whenelectrons are injected from one of the electrodes, and holes areinjected from the other electrode, the luminescent material in theelectroluminescent element is excited to a higher energy level, and theexcessive energy occurring when the excited luminescent body returns tothe ground state, is emitted as light.

In regard to organic electroluminescent elements, research anddevelopment has been conducted in recent years also onelectroluminescent elements which use polymer materials instead of lowmolecular weight compounds.

SUMMARY

According to an aspect of the present invention, there is provided anorganic electroluminescent element including:

a pair of electrodes including a positive electrode and a negativeelectrode, at least one of the electrodes being transparent orsemi-transparent; and

one or more organic compound layers interposed between the pair ofelectrodes, with at least one layer containing one or more chargetransporting polyesters represented by the following formula (I):

wherein in the formula (I), A¹ represents at least one selected fromstructures represented by the following formula (II); Y¹s eachindependently represent a substituted or unsubstituted divalenthydrocarbon group; m's each independently represent an integer of from 1to 5; p represents an integer of from 5 to 5,000; R¹s each independentlyrepresent a hydrogen atom, an alkyl group, a substituted orunsubstituted aryl group, or a substituted or unsubstituted aralkylgroup.

wherein in the formula (II), Ar's each independently represent asubstituted or unsubstituted phenyl group, a substituted orunsubstituted monovalent polynuclear aromatic hydrocarbon group havingtwo aromatic rings, a substituted or unsubstituted monovalent condensedaromatic hydrocarbon group having two or three aromatic rings, or asubstituted or unsubstituted monovalent aromatic heterocyclic group; j'seach independently represent 0 or 1; T's each independently represent adivalent linear hydrocarbon group having from 1 to 6 carbon atoms, or adivalent branched hydrocarbon group having from 2 to 10 carbon atoms;and X represents a group represented by the following formula (III):

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will be described indetail based on the following figures, wherein:

FIG. 1 is a schematic configuration diagram showing the layerconfiguration of an organic electroluminescent element according to anexemplary embodiment of the present invention;

FIG. 2 is a schematic configuration diagram showing the layerconfiguration of an organic electroluminescent element according toanother exemplary embodiment of the present invention;

FIG. 3 is a schematic configuration diagram showing the layerconfiguration of an organic electroluminescent element according toanother exemplary embodiment of the present invention; and

FIG. 4 is a schematic configuration diagram showing the layerconfiguration of an organic electroluminescent element according toanother exemplary embodiment of the present invention.

DETAILED DESCRIPTION

Hereinafter, an exemplary embodiment of the present invention will bedescribed in detail.

<Organic Electroluminescent Element>

The organic electroluminescent element (hereinafter, may be referred toas “organic EL element”) of the exemplary embodiment of the presentinvention includes a pair of electrodes including a positive electrodeand a negative electrode, at least one of the electrodes beingtransparent or semi-transparent, and one or more organic compound layersinterposed between the pair of electrodes, with at least one layercontaining one or more charge transporting polyesters represented byformula (I):

In formula (I), A¹ represents at least one selected from structuresrepresented by formula (II); Y¹s each independently represent asubstituted or unsubstituted divalent hydrocarbon group; m's eachindependently represent an integer of from 1 to 5; p represents aninteger of from 5 to 5,000; and R¹s each independently represent ahydrogen atom, an alkyl group, a substituted or unsubstituted arylgroup, or a substituted or unsubstituted aralkyl group.

In formula (II), Ar's each independently represent a substituted orunsubstituted phenyl group, a substituted or unsubstituted monovalentpolynuclear aromatic hydrocarbon group having two aromatic rings, asubstituted or unsubstituted monovalent condensed aromatic hydrocarbongroup having two or three aromatic rings, or a substituted orunsubstituted monovalent aromatic heterocyclic group; j's eachindependently represent 0 or 1; T's each independently represent adivalent linear hydrocarbon group having from 1 to 6 carbon atoms, or adivalent branched hydrocarbon group having from 2 to 10 carbon atoms;and X represents a group represented by formula (III):

In regard to the charge transporting polyester according to theexemplary embodiment of the present invention, it is speculated thatwhen a dibenzothiophene ring linked to a phenylene group is included inthe molecular structure, the ionization potential is controlled to a lowlevel, and therefore, the charge injectability from the electrode isimproved. Furthermore, the structure containing a dibenzothiophene ringlinked to a phenylene group described above has excellent solubility andcompatibility with solvents or resins. Therefore, it is speculated thatwhen the above-described charge transporting polyester is used, theelement becomes large-area, and organic electroluminescent elements maybe easily produced.

Furthermore, the charge transporting polyester is such that by selectingthe structure that will be described later, the polyester may beimparted with any function of hole transport capability and electrontransport capability, and therefore, the polyester is used in any of ahole transport layer, alight emitting layer, an electron transport layerand the like according to the purpose. In addition, since the chargetransporting polyester according to the exemplary embodiment of thepresent invention has a relatively high glass transition temperature anda large degree of charge mobility, it is speculated that current canflow easily, an increase in the voltage is suppressed, heat is noteasily generated during light emission, so that the polyester hasexcellent stability, and has a lengthened element service life.

Also, according to the exemplary embodiment of the present invention,the term “charge transporting polyester” means a polyester which is asemiconductor capable of transporting holes or electrons as charges.

(Charge Transporting Polyester)

Hereinafter, the charge transporting polyester according to theexemplary embodiment of the present invention will be described indetail. First, the structure of A¹ in the formula (I), which is afeature of the charge transporting polyester, will be explained.

In formula (II), Ar's each independently represent a substituted orunsubstituted phenyl group, a substituted or unsubstituted monovalentpolynuclear aromatic hydrocarbon group having two aromatic rings, asubstituted or unsubstituted monovalent condensed aromatic hydrocarbonhaving two or three aromatic rings, or a substituted or unsubstitutedmonovalent aromatic heterocyclic group. Meanwhile, the two Ar's presentin the formula (II) may be identical with or different from each other,but when two Ar's are identical, production is facilitated.

Here, the polynuclear aromatic hydrocarbon group and the condensedaromatic hydrocarbon group according to the exemplary embodiment of thepresent invention specifically mean groups having polycyclic aromaticrings defined below (that is, a polynuclear aromatic hydrocarbon orcondensed aromatic hydrocarbon).

That is, the term “polynuclear aromatic hydrocarbon” means a hydrocarbonin which two or more aromatic rings each composed of carbon and hydrogenare present, and the rings are bonded through carbon-carbon bonding.Specific examples include biphenyl. Furthermore, the term “condensedaromatic hydrocarbon” means a hydrocarbon compound in which two or morearomatic rings are each composed of carbon and hydrogen, and thesearomatic rings share a pair of carbon atoms that are adjacently bonded.Specific examples include naphthalene, anthracene, phenanthrene, andfluorene.

Furthermore, according to the exemplary embodiment of the presentinvention, the aromatic heterocyclic group selected as a structurerepresenting Ar in the formula (II) means a group having an aromaticheterocyclic ring defined below.

That is, the term “aromatic heterocyclic ring” means an aromatic ringwhich also contains elements other than carbon and hydrogen, and forexample, compounds in which the number of atoms (Nr) constituting thering skeleton is at least any one of 5 and 6. Furthermore, the type andnumber of atoms other than the carbon atoms constituting the ringskeleton (heteroatoms) are not particularly limited, but for example, asulfur atom, a nitrogen atom, an oxygen atom and the like are used.Thus, the ring skeleton may contain at least any of two or more kinds ofheteroatoms and two or more heteroatoms. Particularly, as a heterocyclicring having a 5-membered ring structure, for example, thiophene,pyrrole, furan, and heterocyclic rings in which the carbon at the3-position and the 4-position of the above-described compounds aresubstituted with nitrogen, are used, and as a heterocyclic ring having a6-membered ring structure, for example, pyridine is used.

Furthermore, it is desirable that the aromatic heterocyclic group havethe aromatic heterocyclic ring described above, and the aromaticheterocyclic group contain, in addition to the group constituted of thearomatic heterocyclic ring, both a group in which an aromatic ring issubstituted with the aromatic heterocyclic ring, and a group in whichthe aromatic heterocyclic ring is substituted with an aromatic ring.Specific examples of the aromatic ring include those aromatic ringsdescribed above.

That is, the aromatic heterocyclic group may be, for example, a group ofthe polycyclic aromatic ring described above (that is, a monovalentpolynuclear aromatic hydrocarbon having two or more aromatic rings, or amonovalent condensed aromatic hydrocarbon having two or more aromaticrings), in which one or more aromatic rings are substituted with anaromatic heterocyclic ring, and specific examples include athiophenylphenyl group, a phenylpyridine group, and a phenylpyrrolegroup.

In formula (II), examples of the substituent used to further substitutethe phenyl group, polynuclear aromatic hydrocarbon group, condensedaromatic hydrocarbon group and aromatic heterocyclic group that arerepresented by Ar, include a hydrogen atom, an alkyl group, an alkoxygroup, an aryl group, an aralkyl group, a substituted amino group, and ahalogen atom.

The alkyl group may be, for example, an alkyl group having from 1 to 10carbon atoms, and examples include a methyl group, an ethyl group, apropyl group, and an isopropyl group.

The alkoxy group may be, for example, an alkoxy group having from 1 to10 carbon atoms, and examples include a methoxy group, an ethoxy group,a propoxy group, and an isopropoxy group.

The aryl group may be, for example, an aryl group having from 6 to 20carbon atoms, and examples include a phenyl group and a toluoyl group.

The aralkyl group may be, for example, an aralkyl group having from 7 to20 carbon atoms, and examples include a benzyl group and a phenethylgroup.

Examples of the substituent of the substituted amino group include analkyl group, an aryl group and an aralkyl group, and specific examplesare as described above.

In formula (II), T's each independently represent a divalent linearhydrocarbon group having from 1 to 6 carbon atoms, or a divalentbranched hydrocarbon group having from 2 to 10 carbon atoms, and amongthem, examples include a divalent linear hydrocarbon group having from 2to 6 carbon atoms and a divalent branched hydrocarbon group having from3 to 7 carbon atoms. Among these, more specific examples include, inparticular, divalent hydrocarbon groups shown below.

In formula (II), j's each independently represent 0 or 1.

In addition, T and j that are respectively present twice in the formula(II), may be identical with or different from each other, but when thetwo are identical, the production of the charge transporting polyesteris much easier.

The at least one selected from the structures represented by the formula(II) explained above is A¹ in the charge transporting polyesterrepresented by formula (I).

In addition, the plural A¹s present in the charge transporting polyesterrepresented by the formula (I) may have the same structure or may havedifferent structures.

In the formula (I), Y¹s each independently represent a substituted orunsubstituted divalent hydrocarbon group. The divalent hydrocarbon grouprepresented by Y¹ is a divalent alcohol residue, and examples include analkylene group, a (poly)ethyleneoxy group, a (poly)propyleneoxy group,an arylene group, a divalent heterocyclic group and combinationsthereof. The carbon number of the divalent hydrocarbon group representedby Y¹ may be, for example, in the range of from 1 to 18, and the carbonnumber may also be in the range of from 1 to 6.

That is, specific examples of the divalent hydrocarbon group representedby Y¹ include an alkylene group having from 1 to 10 carbon atoms, and anarylene group having from 6 to 18 carbon atoms, and the divalenthydrocarbon group may also be an alkylene group having from 1 to 5carbon atoms.

Specific examples of Y¹ include groups selected from among the followingformulas (IV-1) to (IV-8).

Meanwhile, the plural Y¹s present in the charge transporting polyesterrepresented by the formula (I) may be identical with or different fromeach other.

In the formulas (IV-1), (IV-2), (IV-5) and (IV-6), R³ and R⁴ eachrepresent a hydrogen atom, a substituted or unsubstituted alkyl grouphaving from 1 to 4 carbon atoms, a substituted or unsubstituted alkoxygroup having from 1 to 4 carbon atoms, a substituted or unsubstitutedphenyl group, a substituted or unsubstituted aralkyl group, or a halogenatom; a, b and c each independently represent an integer of from 1 to10; e represents an integer of from 0 to 2; d and f represent 0 or 1;and V represents a group represented by the following formulas (V-1) to(V-12)

In the formulas (V-1), (V-10), (V-11) and (V-12), represents an integerof from 1 to 20; and h represents an integer of from 0 to 10.

In the formula (I), m's each independently represent an integer of from1 to 5, and the plural m's present in the charge transporting polyesterrepresented by the formula (I) may be identical with or different fromeach other.

In the formula (I), R's each independently represent a hydrogen atom, analkyl group, a substituted or unsubstituted aryl group, or a substitutedor unsubstituted aralkyl group. Specific examples of the alkyl group,aryl group and aralkyl group as well as the substituents substitutingthese groups are the same as the specific examples mentioned as thesubstituents substituting the aromatic ring of Ar.

Furthermore, in the formula (I), R¹ may be a hydrogen atom or a phenylgroup among the examples described above, and from the viewpoints ofcost reduction and the ease of production, R¹ may be a hydrogen atom.Two R¹s in the formula (I) may be identical with or different from eachother, but when the two are identical, the production of the chargetransporting polyester is much easier.

In the formula (I), p represents an integer of from 5 to 5,000, but mayalso be in the range of from 10 to 1000.

More specifically, the weight average molecular weight Mw of the chargetransporting polyester may be, for example, in the range of from 5,000to 300,000, and may also be in the range of from 10,000 to 100,000.

The weight average molecular weight Mw is measured by the followingmethod. That is, the weight average molecular weight is measured bypreparing a 1.0% by mass tetrahydrofuran solution of the chargetransporting polyester, and performing gel permeation chromatography(GPC) using a differential refractive index detector (RI) and usingstyrene polymers as standard samples.

Furthermore, the glass transition temperature (Tg) of the chargetransporting polyester may be, for example, from 60° C. to 300° C., andmay also be from 100° C. to 200° C.

Meanwhile, the glass transition temperature is measured with adifferential scanning calorimeter using α-Al₂O₃ as a reference, byincreasing the temperature of the sample to a rubbery state, immersingthe sample in liquid nitrogen to quench the sample, and then increasingthe temperature of the sample again under the conditions of a rate oftemperature increase of 10° C./min.

The charge transporting polyester represented by the formula (I) issynthesized by, for example, polymerizing a charge transporting monomerrepresented by the following structural formula (VI) by a known methoddescribed in, for example, “Lectures on Experimental Chemistry, 4^(th)Edition”, Vol. 28 (edited by the Chemical Society of Japan, Maruzen Co.,Ltd., 1992) or the like.

In the formula (VI), Ar, X, T and j are the same as Ar, X, T and jdefined for formula (II), respectively. In the formula (VI), A²represents a hydroxyl group, a halogen atom, or —O—R⁵ (wherein R⁵represents a substituted or unsubstituted alkyl group, a substituted orunsubstituted aryl group, or a substituted or unsubstituted aralkylgroup).

Here, specific examples of the structure represented by formula (VI) areshown in Table 1 to Table 3. In the following, for each of the specificexamples of the charge transporting monomer designated with a compoundnumber (structure number) in Tables 1 to 3, for example, a specificexample designated with number 5 will be denoted as “Monomer compound(5)”.

In the specific examples of the charge transporting monomer shown inTables 1 to 3, Ar, T, j and A² that are present twice in the formula(VI) are respectively the same.

TABLE 1 Structure No. Ar  j  T A²  1

0 CH₂CH₂ OCH₃  2

0 CH₂CH₂ OCH₃  3

0 CH₂CH₂ OCH₃  4

0 CH₂CH₂ OCH₃  5

0 CH₂CH₂ OCH₃  6

1 CH₂CH₂ OCH₃  7

1 CH₂CH₂ OCH₃  8

1 CH₂CH₂ OCH₃  9

1 CH₂CH₂ OCH₃ 10

1 CH₂CH₂ OCH₃

TABLE 2 Structure No. Ar  j  T A² 11

1 CH₂CH₂ OCH₃ 12

1 CH₂CH₂ OCH₃ 13

1 CH₂CH₂ OCH₃ 14

1 CH₂CH₂ OCH₃ 15

1 CH₂CH₂ OCH₃ 16

1 CH₂CH₂ OCH₃ 17

1 CH₂CH₂ OCH₃ 18

1 CH₂CH₂ OCH₃ 19

1 CH₂CH₂ OCH₃ 20

1 CH₂CH₂ OCH₃

TABLE 3 Structure No. Ar  j  T A² 21

1 CH₂CH₂ OCH₃ 22

1 CH₂CH₂ OCH₃ 23

1 CH₂CH₂ OCH₃ 24

1 CH₂CH₂ OCH₃ 25

1 CH₂CH₂ OCH₃ 26

1 CH₂CH₂ OCH₃

Here, first, the method for synthesizing the charge transporting monomerrepresented by formula (VI) will be described. An example of the methodfor synthesizing the charge transporting monomer will be shown below,but the method is not limited to this.

As the method for synthesizing the charge transporting monomer(dibenzothiophene compound) represented by the formula (VI), forexample, a method using the cross-coupling biaryl synthesis may bementioned. Specific examples of the cross-coupling biaryl synthesisinclude, for example, a Suzuki reaction, a Kharasch reaction, a Negishireaction, a Stille reaction, a Grignard reaction, and an Ullmannreaction.

A specific example of the method for synthesizing the chargetransporting monomer represented by formula (VI) may be, for example, asynthesis method based on a cross-coupling reaction between a compoundrepresented by formula (VII) and a compound represented by formula(VIII) as shown in the following formula, but the synthesis method isnot limited to this.

In the formula (VII) and formula (VIII), X and G each represent ahalogen atom, B(OH)₂, a substituent represented by the followingstructural formula (X-1), a substituent represented by the followingstructural formula (X-2), or a substituent represented by the followingstructural formula (X-3). Furthermore, in the formula (VII) and formula(IX), A², T, j and Ar respectively have the same meanings as A², T, jand Ar in the formula (VI).

Furthermore, during the reaction described above, a metal, a metalcomplex catalyst, a base, a solvent or the like may also be used asnecessary.

Examples of the metal that may be used include palladium (Pd), copper(Cu), titanium (Ti), tin (Sn), nickel (Ni), and platinum (Pt).

Examples of the metal complex that may be used includetetrakis(triphenylphosphine)palladium (Pd(PPh₃)₄), palladium(II) acetate(Pd(OCOCH₃)₂), tris(dibenzylideneacetone)dipalladium(0) (Pd₂(dba)₃),di(triphenylphosphine)dichloropalladium (Pd(PPh₃)₂Cl₂),1,1′-bis(diphenylphosphino) ferrocene-palladium(II)dichloride-dichloromethane complex (Pd(dppf)₂Cl₂), Pd/C, and nickel(II)acetylacetonate (Ni(acac)₂).

Examples of the base that may be used include inorganic bases such assodium carbonate (Na₂CO₃), potassium carbonate (K₂CO₃), cesium carbonate(Cs₂CO₃), and barium hydroxide (Ba(OH)₂); and organic bases such astriethylamine (NEt₃), diisopropylamine (NH(i-Pr)₂), diethylamine(NHEt₂), dimethylamine (NHMe₂), trimethylamine (NMe₃),1,8-diazabicyclo[5.4.0]-7-undecene (DBU), N,N-dimethyl-4-aminopyridine(DMAP), and pyridine.

It is preferable that the solvent be a solvent that does notsignificantly inhibit the reaction, and examples that may be usedinclude aromatic hydrocarbon solvents such as benzene, toluene, xylene,and mesitylene; ether solvents such as diethyl ether, tetrahydrofuran,and dioxane; acetonitrile, dimethylformamide, dimethyl sulfoxide,methanol, ethanol, isopropyl alcohol, and water.

Furthermore, during the reaction described above, if necessary, forexample, triphenylphosphine (PPh₃), tri-o-tolylphosphine (P(o-Tol)₃),tributylphosphine (P(t-Bu)₃), and triethylphosphine (PEt₃) are used.

Meanwhile, Me represents “CH₃”; Et represents “C₂H₅”; Ph represents“C₆H₅”; i-Pr represents “(CH₃)₂CH₂”; o-Tol represents “o-CH₃C₆H₄”; andt-Bu represents “(CH₃)₃C”.

The reaction may be carried out, for example, under normal pressure, inan inert gas atmosphere of nitrogen, argon or the like, but the reactionmay also be carried out under pressurized conditions.

The reaction temperature for the reaction may be, for example, in therange of from 20° C. to 300° C., but may also be in the range of from50° C. to 180° C. The reaction time may vary depending on the reactionconditions, but for example, the reaction time may be selected in therange of from 5 minutes to 20 hours.

The use amount of the metal or metal complex catalyst is notparticularly limited, but for example, the use amount may be in therange of from 0.001 mole to 10 moles, or may also be in the range offrom 0.01 mole to 5.0 moles, based on one mole of the compoundrepresented by formula (VII).

The use amount of the base may be in the range of from 0.5 mole to 4.0moles, or may also be in the range of from 1.0 mole to 2.5 moles, basedon one mole of the compound represented by formula (VII).

After the reaction described above, for example, the reaction solutionis introduced into water, and then the mixture is stirred. When thereaction product is in the form of crystals, a crude product is obtainedby collecting the reaction product by suction filtration. When thereaction product is an oily matter, for example, a crude product isobtained by extracting the reaction product with a solvent such as ethylacetate or toluene. The crude product thus obtained may be purifiedusing a column packed with, for example, silica gel, alumina, activatedwhite clay or activated carbon, or the crude product may also besubjected to a treatment of adsorbing unnecessary components by addingthese adsorbents to the solution. Furthermore, if the reaction productis in the form of crystals, the crystals may also be purified byrecrystallization from a solvent such as hexane, methanol, acetone,ethanol, ethyl acetate or toluene.

However, the synthesis method according to the exemplary embodiment ofthe present invention is not intended to be limited to these.

When polymerization is carried out by a known method using the chargetransporting monomer represented by the formula (VI) obtained asdescribed above, the charge transporting polyester represented by theformula (I) is synthesized.

Specifically, for example, a method of introducing a substituent thatwill be described below into the end of the charge transporting monomer(that is, A² in formula (VI)) may be used, and more specifically, thefollowing synthesis method may be employed.

1) In case where A² is a hydroxyl group

The compound represented by the formula (VI) and a divalent alcoholrepresented by HO—(Y¹—O)_(m)—H are mixed in equal amounts (mass ratio),and the mixture is polymerized using an acid catalyst. Meanwhile, Y¹ andm have the same meanings as Y¹ and m defined for the formula (I).

As the acid catalyst, those conventionally used in ordinaryesterification reactions, such as sulfuric acid, toluenesulfonic acid,and trifluoroacetic acid are used, and the acid catalyst is used in anamount of, for example, from 1/10,000 part by mass to 1/10 part by mass,relative to 1 part by mass of the monomer (that is, the compoundrepresented by the formula (VI)). The acid catalyst may also be used inthe range of from 1/1,000 part by mass to 1/50 part by mass.

In order to remove water produced during the polymerization, forexample, a solvent that is azeotropically boiled with water is used.Specifically, for example, toluene, chlorobenzene, 1-chloronaphthaleneand the like are effective, and the solvent is used in an amount in therange of, for example, from 1 part by mass to 100 parts by mass relativeto 1 part by mass of the monomer. The solvent may also be used in anamount in the range of from 2 parts by mass to 50 parts by mass.

The reaction temperature is set according to the conditions, but inorder to remove the water produced during the polymerization, thereaction may be carried out at the boiling point of the solvent.

After completion of the reaction, if a solvent has not been used, thereaction product is dissolved in a solvent which dissolves the reactionproduct. If a solvent has been used, the reaction solution may bedirectly added dropwise into a poor solvent in which a polymer is noteasily dissolved, such as an alcohol such as methanol or ethanol, oracetone, to thereby precipitate a polyester. The polyester is separated,subsequently washed with water or an organic solvent, and dried.

Furthermore, if necessary, a reprecipitation treatment of dissolving thereaction product in an appropriate organic solvent, adding the solutiondropwise into a poor solvent, and precipitating a polyester may berepeated. At the time of the reprecipitation treatment, the treatmentmay also be carried out while stirring the system efficiently with amechanical stirrer or the like. The solvent that dissolves the polyesterat the time of the reprecipitation treatment is used in an amount of,for example, from 1 part by mass to 100 parts by mass, relative to 1part by mass of the polyester, and the solvent may also be used in anamount in the range of from 2 parts by mass to 50 parts by mass.Furthermore, the poor solvent is used in an amount in the range of, forexample, from 1 part by mass to 1,000 parts by mass relative to 1 partby mass of the polyester, and may also be used in an amount in the rangeof from 10 parts by mass to 500 parts by mass.

2) In case where A² is halogen

The compound represented by the formula (VI) and a divalent alcoholrepresented by HO—(Y¹—O)_(m)—H are mixed in equal amounts (mass ratio),and the mixture is polymerized using an organic basic catalyst such aspyridine or triethylamine. Meanwhile, Y¹ and m described above have thesame meanings as Y¹ and m defined for the formula (I).

The organic basic catalyst is used in an amount in the range of, forexample, from 1 part by mass to 10 parts by mass relative to 1 part bymass of the monomer, and may also be used in an amount in the range offrom 2 parts by mass to 5 parts by mass.

As the solvent, methylene chloride, tetrahydrofuran (THF), toluene,chlorobenzene, 1-chloronaphthalene and the like are effective, and thesolvent is used in an amount in the range of, for example, from 1 partby mass to 100 parts by mass relative to 1 part by mass of the monomer(that is, the compound represented by the formula (VI)), and may also beused in an amount in the range of from 2 parts by mass to 50 parts bymass.

The reaction temperature is set according to the conditions. After thepolymerization, the reaction product is subjected to a reprecipitationtreatment as described above, and is purified.

Furthermore, in the case of using a divalent alcohol having highacidity, such as bisphenol, an interfacial polymerization method mayalso be used. That is, polymerization is carried out by adding adivalent alcohol to water, adding an equal amount (mass ratio) of a baseto dissolve therein, and adding a divalent alcohol and an equal amountof a monomer solution thereto while vigorously stirring the system. Atthis time, water is used in an amount in the range of, for example, from1 part by mass to 1,000 parts by mass relative to 1 part by mass of thedivalent alcohol, and may also be used in an amount in the range of from2 parts by mass to 500 parts by mass. As the solvent to dissolve themonomer, methylene chloride, dichloroethane, trichloroethane, toluene,chlorobenzene, 1-chloronaphthalene and the like are effective.

The reaction temperature is set according to the conditions, and inorder to accelerate the reaction, it is effective to use a phasetransfer catalyst such as an ammonium salt or a sulfonium salt. Thephase transfer catalyst is used in an amount of, for example, in therange of from 0.1 part by mass to 10 parts by mass relative to 1 part bymass of the monomer, and may also be used in an amount in the range offrom 0.2 part by mass to 5 parts by mass.

3) In case where A² is —O—R⁵

An excess amount of divalent alcohol represented by HO—(Y¹—O)_(m)—H isadded to the compound represented by the formula (VI), the mixture isheated using an inorganic acid such as sulfuric acid or phosphoric acid,titanium alkoxide, an acetate or carbonate of calcium, cobalt or thelike, or an oxide of zinc or lead as a catalyst, and the product issynthesized by a transesterification reaction. Meanwhile, Y¹ and m havethe same meanings as Y¹ and m in the formula (1).

The divalent alcohol is used in an amount in the range of, for example,from 2 parts by mass to 100 parts by mass relative to 1 part by mass ofthe monomer (compound represented by the formula (VI)), and may also beused in an amount in the range of from 3 parts by mass to 50 parts bymass.

The catalyst is used in an amount in the range of, for example, from1/10,000 part by mass to 1 part by mass relative to 1 part by mass ofthe monomer, and may also be used in an amount in the range of from1/1,000 part by mass to ½ part by mass.

The reaction is carried out at a reaction temperature of from 200° C. to300° C., and after completion of the transesterification reaction from—O—R⁵ to —O—(Y¹—O)_(m)—H, the reaction is carried out, for example,under reduced pressure in order to accelerate polymerization through thedetachment of HO—(Y¹—O)_(m)—H. Furthermore, a high-boiling point solventsuch as 1-chloronaphthalene, which azeotropically boils withHO—(Y¹—O)_(m)—H, is used, and the reaction may be carried out whileHO—(Y¹—O)_(m)—H is azeotropically removed at normal pressure.

Also, the polyester may also be synthesized as follows.

For each of the cases of items 1) to 3), a compound represented by thefollowing formula (XI) is produced by adding a divalent alcohol inexcess and carrying out the reaction, and then this compound is usedinstead of the monomer represented by the formula (VI) to react with adivalent carboxylic acid, a divalent carboxylic acid halide or the like.Thus, the polyester represented by the formula (I) is obtained.

In the formula (XI), Ar, X, T and j have the same meanings as Ar, X, Tand j defined for the formula (II), respectively, and Y¹ and m have thesame meanings as Y¹ and m defined for the formula (I), respectively.

Among the synthesis methods of the items 1) to 3), for the chargetransporting polyester according to the exemplary embodiment of thepresent invention, it is easy to carry out the production according tothe synthesis method of 1).

Here, specific examples of the charge transporting polyester representedby the formula (I) are shown in Table 4 to Table 6, but the chargetransporting polyester according to the exemplary embodiment of thepresent invention is not limited to these specific examples.Furthermore, in Tables 4 to 6, the number indicated in the column of A¹of the row of a monomer (column of “Structure of A¹ in formula (I)”)corresponds to the structure number of the specific examples of thestructure represented by the formula (II) (“structure number” of thecharge transporting monomer in Table 1 to Table 3).

Hereinafter, for each of the specific examples of the chargetransporting polyester designated with a compound number (polymercompound number) in the Tables 4 to 6, for example, a specific exampledesignated with the number 15 is referred to as “Exemplary compound(15)”. Furthermore, in each of the specific examples of the chargetransporting polyester shown in Tables 4 to 6, Y¹, m and R¹ that arepresent twice in the formula (I) are respectively the same.

TABLE 4 Struc- Poly- ture of mer A¹ in Com- formula pound (I) Y¹  m  R¹p  1 1

1 H 55  2 1

1 H 58  3 1

1 H 48  4 1

1 H 65  5 1

1 H 57  6 4

1 H 57  7 4

1 H 38  8 4

1 H 58  9 4

1 H 74 10 6

1 H 80

TABLE 5 Structure Polymer of A¹ in Compound formula (I) Y¹ m R¹ p 11  6

1 H 71 12  7

1 H 67 13  9

1 H 52 14 10

1 H 56 15 12

1 H 69 16 14

1 H 71 17 14

1 H 58 18 15

1 H 49 19 15

1 H 61 20 17

1 H 57

TABLE 6 Poly- Structure mer of A¹ in Com- formula pound (I) Y¹ m R¹ p 2118

1 H 68 22 19

1 H 68 23 23

1 H 83 24 23

1 H 58 25 24

1 H 68 26 24

1 H 55 27 25

1 H 62 28 26

1 H 59

Next, the configuration of the organic electroluminescent element of theexemplary embodiment of the present invention will be described indetail.

The organic electroluminescent element of the exemplary embodiment ofthe present invention includes a pair of electrodes, with at least oneof the electrodes being transparent or semi-transparent, and one or moreorganic compound layers interposed between those electrodes, and thelayer configuration is not particularly limited as long as at least onelayer of the organic compound layers contains one of the chargetransporting polyesters described above.

In the organic electroluminescent element of the exemplary embodiment ofthe present invention, when there is one organic compound layer, theorganic compound layer means a light emitting layer having chargetransport capability, and the light emitting layer contains the chargetransporting polyester. When there are plural organic compound layers(that is, in the case of a functionally separated type with therespective layers having different functions), at least one of thelayers becomes a light emitting layer, and this light emitting layer maybe a light emitting layer having charge transport capability. In thiscase, specific examples of the layer configuration including the lightemitting layer or a light emitting layer having charge transportcapability, and other layers include the following items (1) to (3).

(1) Layer configuration composed of a light emitting layer and at leastany one of an electron transport layer and an electron injection layer.

(2) Layer configuration composed of at least any one of a hole transportlayer and a hole injection layer, a light emitting layer, and at leastany one of an electron transport layer and an electron injection layer.

(3) Layer configuration composed of at least any one of a hole transportlayer and a hole injection layer, and a light emitting layer.

The layers other than the light emitting layer, and the light emittinglayer having charge transport capability, of these layer configurations(1) to (3) have a function as a charge transport layer or a chargeinjection layer.

Meanwhile, it is desirable that all of these layer configurations of (1)to (3) contain the charge transporting polyester in any one layer.

Furthermore, in the organic electroluminescent element of the exemplaryembodiment, the light emitting layer, the hole transport layer, the holeinjection layer, the electron transport layer and the electron injectionlayer may further contain a charge transporting compound (a holetransporting material or an electron transporting material) other thanthe charge transporting polyester. The details of the chargetransporting compound will be described below.

Hereinafter, the organic electroluminescent element of the exemplaryembodiment of the present invention will be described in more detailwith reference to drawings, but the organic electroluminescent elementis not intended to be limited to these.

FIG. 1 to FIG. 4 are schematic cross-sectional diagrams for explainingthe layer configurations of the organic electroluminescent element ofthe exemplary embodiment of the present invention. FIG. 1, FIG. 2 andFIG. 3 show examples of the case where there are plural organic compoundlayers, and FIG. 4 shows an example of the case where there is oneorganic compound layer. Meanwhile, in FIG. 1 to FIG. 4, members havingthe same function will be described under the same reference numeral.

The organic electroluminescent element shown in FIG. 1 has aconfiguration in which on a transparent insulator substrate 1, atransparent electrode 2, a light emitting layer 4, at least one layer 5of an electron transport layer and an electron injection layer, and aback surface electrode 7 are laminated in sequence, and this correspondsto the layer configuration (1). However, when the layer designated withReference Numeral 5 is composed of an electron transport layer and anelectron injection layer, the electron transport layer, the electroninjection layer and the back surface electrode 7 are laminated in thisorder on the back surface electrode 7 side of the light emitting layer4.

The organic electroluminescent element shown in FIG. 2 has aconfiguration in which on a transparent insulator substrate 1, atransparent electrode 2, at least one layer 3 of a hole transport layerand a hole injection layer, a light emitting layer 4, at least one layer5 of an electron transport layer and an electron injection layer, and aback surface electrode 7 are laminated in sequence, and this correspondsto the layer configuration (2). However, when the layer designated withReference Numeral 3 is constituted of a hole transport layer and a holeinjection layer, the hole injection layer, the hole transport layer andthe light emitting layer 4 are laminated in this order on the backsurface electrode 7 side of the transparent electrode 2. Furthermore,when the layer designated with Reference Numeral 5 is composed of anelectron transport layer and an electron injection layer, the electrontransport layer, the electron injection layer, and the back surfaceelectrode 7 are laminated in this order on the back surface electrode 7of the light emitting layer 4.

The organic electroluminescent element shown in FIG. 3 has aconfiguration in which on a transparent insulator substrate 1, atransparent electrode 2, at least one layer 3 of a hole transport layerand a hole injection layer, a light emitting layer 4 and a back surfaceelectrode 7 are laminated in sequence, and this corresponds to the layerconfiguration (3). However, when the layer designated with ReferenceNumeral 3 is composed of a hole transport layer and a hole injectionlayer, the hole injection layer, the hole transport layer and the lightemitting layer 4 are laminated in this order on the back surfaceelectrode 7 side of the transparent electrode 2.

The organic electroluminescent element shown in FIG. 4 has aconfiguration in which on a transparent insulator substrate 1, atransparent electrode 2, a light emitting layer 6 having chargetransport capability, and a back surface electrode 7 are laminated insequence.

Furthermore, when the organic electroluminescent element has a topemission structure or is made as a transmissive type using transparentelectrodes for both the negative electrode and the positive electrode, astructure in which the layer configurations of FIG. 1 to FIG. 4 arestacked in plural stages is also realized.

Hereinafter, each of the configurations will be described in detail.

The charge transporting polyester according to the exemplary embodimentof the present invention is also imparted with any of hole transportcapability and electron transport capability through the function of theorganic compound layer in which the polyester is included.

For example, in the layer configuration of the organicelectroluminescent element shown in FIG. 1, the charge transportingpolyester may be included in any one of the light emitting layer 4 andat least one layer 5 of the electron transport layer and the electroninjection layer, and acts as all of the light emitting layer 4 and theat least one layer 5 of the electron transport layer and the electroninjection layer. Furthermore, in the case of the layer configuration ofthe organic electroluminescent shown in FIG. 2, the charge transportingpolyester may be included in at least one layer 3 of the hole transportlayer and the hole injection layer, the light emitting layer 4 and theat least one layer 5 of the electron transport layer and the electroninjection layer, and acts as all of the at least one layer 3 of the holetransport layer and the hole injection layer, the light emitting layer4, and the at least one layer 5 of the electron transport layer and theelectron injection layer. Furthermore, in the case of the layerconfiguration of the organic electroluminescent element shown in FIG. 3,the charge transporting polyester may be included in any one of the atleast one layer 3 of the hole transport layer and the hole injectionlayer, and the light emitting layer 4, and acts as all of the at leastone layer 3 of the hole transport layer and the hole injection layer,and the light emitting layer 4. Furthermore, in the case of the layerconfiguration of the organic electroluminescent element shown in FIG. 4,the charge transporting polyester is included in the light emittinglayer 6 having charge transport capability, and acts as the lightemitting layer 6 having charge transport capability.

In the case of the layer configurations of the organicelectroluminescent element shown in FIG. 1 to FIG. 4, a transparentsubstrate may be used to extract emitted light for the transparentinsulator substrate 1, and a glass plate, a plastic film and the likemay be used, but the substrate is not limited to these. The term“transparent” means that the transmittance of light in the visibleregion is 10% or higher, and the transmittance may be 75% or higher.Hereinafter, the transmittance is equivalent to this value.

Furthermore, the transparent electrode 2 is transparent orsemi-transparent so that emitted light is extracted at a levelequivalent to that of the transparent insulator substrate, and in orderto carry out injection of holes, an electrode having a large workfunction may be used. An example may be an electrode having a workfunction of 4 eV or higher. The term “semi-transparent” means that thetransmittance of light in the visible region is 70% or higher, and thetransmittance may be 80% or higher. Hereinafter, the transmittance isequivalent to this value.

As specific examples, oxide films of indium tin oxide (ITO), tin oxide(NESA), indium oxide, zinc oxide and the like, and deposited orsputtered gold, platinum, palladium and the like are used, but theelectrode is not limited to these. The sheet resistance of the electrodeis such that a lower value is more desirable, and the sheet resistancemay be several hundred Ω/□ or less, or may also be 100Ω/□ or less. Thetransparent electrode may have a transmittance of light in the visibleregion of 10% or higher in equivalence to the transparent insulatorsubstrate, and the transmittance may also be 75% or higher.

In the case of the layer configurations of the organicelectroluminescent element shown in FIG. 1 to FIG. 3, the electrontransport layer or the hole transport layer may be formed from thecharge transporting polyester alone, to which a function (electrontransport capability or hole transport capability) is imparted accordingto the purpose. However, for example, in order to regulate the holemobility, the layer may also be formed by mixing and dispersing a holetransporting material other than the charge transporting polyester in anamount in the range of 0.1% by mass to 50% by mass relative to the totalamount of the materials constituting the layer.

Examples of the hole transporting material include atetraphenylenediamine derivative, a triphenylamine derivative, acarbazole derivative, a stilbene derivative, a spirofluorene derivative,an arylhydrazone derivative, and a porphyrin compound, and among these,examples having good compatibility with the charge transportingpolyester include a tetraphenylenediamine derivative, a spirofluorenederivative, and a triphenylamine derivative.

In the case of regulating the electron mobility, the layer may be formedby mixing and dispersing the electron transporting material in an amountof from 0.1% by mass to 50% by mass relative to the total amount of thematerial constituting the layer.

Examples of the electron transporting material include an oxadiazolederivative, a nitro-substituted fluorenone derivative, a diphenoquinonederivative, a thiopyran dioxide derivative, a silol derivative, achelate type organometallic complex, a polynuclear or condensed aromaticring compound, a perylene derivative, a triazole derivative, and afluorenylidenemethane derivative.

Furthermore, when regulation is required in both the hole mobility andthe electron mobility, both the hole transporting material and theelectron transporting material may be incorporated together into thecharge transporting polyester.

Furthermore, for the purpose of an improvement of the film-formingproperties, prevention of pinholes, and the like, an appropriate resin(polymer) and additives may also be added. Specific examples of theresin that may be used include electrically conductive resins such as apolycarbonate resin, a polyester resin, a methacrylic resin, an acrylicresin, a polyvinyl chloride resin, a cellulose resin, a urethane resin,an epoxy resin, a polystyrene resin, a polyvinyl acetate resin, astyrene-butadiene copolymer, a vinylidene chloride-acrylonitrilecopolymer, a vinyl chloride-vinyl acetate-maleic anhydride copolymer, asilicone resin, a poly-N-vinylcarbazole resin, a polysilane resin,polythiophene, and polypyrrole. Here, the term conductivity means that,for example, the volume resistivity is in the range of 1.0×10⁹ Ω·cm orless, and the same applies in the following descriptions. Furthermore,as the additives, known antioxidants, ultraviolet absorbents,plasticizers and the like may be used.

Furthermore, in the case of enhancing charge injectability, a holeinjection layer or an electron injection layer may be used, and examplesof a hole injecting material that may be used include a triphenylaminederivative, a phenylenediamine derivative, a phthalocyanine derivative,an indanthrene derivative, and a polyalkylenedioxythiophene derivative.Furthermore, a Lewis acid, sulfonic acid and the like may beincorporated into these materials. Examples of an electron injectingmaterial that may be used include metals such as lithium (Li), calcium(Ca), barium (Ba), strontium (Sr), silver (Ag) and gold (Au); metalfluorides such as LiF and MgF; and metal oxides such as MgO, Al₂O₃, andLiO.

Furthermore, when the charge transporting polyester is used for afunction other than the light emitting function, a luminescent compoundis used as the light emitting material. As the light emitting material,a compound that exhibits high light emission quantum efficiency in thesolid state is used. The light emitting material may be any of a lowmolecular weight compound and a polymeric compound, and specificexamples of an organic low molecular weight compound include a chelatetype organometallic complex, a polynuclear or condensed aromatic ringcompound, a perylene derivative, a coumarin derivative, a styrylarylenederivative, a silol derivative, an oxazole derivative, anoxabenzothiazole derivative, an oxathiazole derivative, and anoxadiazole derivative, while specific examples of a polymeric compoundthat may be used include a polyparaphenylene derivative, apolyparaphenylenevinylene derivative, a polythiophene derivative, and apolyacetylene derivative. Specific examples include the followingcompounds (XV-1) to (XV-17), but the examples are not limited to these.

Meanwhile, in the structural formulas (XV-13) to (XV-17), V representsthe same divalent organic group as Y¹; and n and g each independentlyrepresent an integer of 1 or greater.

Furthermore, for the purpose of an enhancement of the durability of theorganic electroluminescent element or an enhancement of the lightemission efficiency of the element, a dye compound which is differentfrom the light emitting material may be doped as a guest material intothe light emitting material or the charge transporting polyester. Theproportion of the dye compound doped may be 0.001% by mass to 40% bymass of the object layer, and may also be 0.01% by mass to 10% by mass.As the dye compound used in this doping, an organic compound which hasgood compatibility with the light emitting material and does notinterfere in satisfactory film formation of the light emitting layer isused, and specific examples include a coumarin derivative, a DCMderivative, a quinacridone derivative, a perimidone derivative, abenzopyran derivative, a rhodamine derivative, benzothioxanthenederivative, a rubrene derivative, a porphyrin derivative, and metalcomplex compounds of ruthenium, rhodium, palladium, silver, rhenium,osmium, iridium, platinum, gold and the like.

Specific examples of the dye compound include the following compounds(XVI-1) to (XVI-6), but the examples are not limited to these.

Furthermore, the light emitting layer 4 may be formed of the lightemitting material alone, but for the purpose of further improving theelectrical characteristics and light emitting characteristics, the lightemitting layer may be formed by mixing the charge transporting polyesterinto the light emitting material in an amount in the range of 1% by massto 50% by mass, and dispersing the mixture. Alternatively, the lightemitting layer may be formed by mixing a charge transporting materialother than the charge transporting polyester into the light emittingmaterial in an amount in the range of 1% by mass to 50% by mass, anddispersing the mixture. Furthermore, when the charge transportingpolyester also has light emitting characteristics, the chargetransporting material may also be used as a light emitting material, andin that case, for the purpose of further improving the electricalcharacteristics and light emitting characteristics, the light emittinglayer may be formed by mixing and dispersing a charge transportingmaterial other than the charge transporting polyester in an amount inthe range of 1% by mass to 50% by mass.

In the case of the layer configuration of the organic electroluminescentelement shown in FIG. 4, the light emitting layer 6 having chargetransport capability is an organic compound layer in which a lightemitting material (specifically, for example, at least one selected fromthe light emitting materials (XV-1) to (XV-17)) is dispersed in thecharge transporting polyester imparted with a function (hole transportcapability or electron transport capability) according to the purpose,in an amount of 50% by mass or less. However, in order to adjust thebalance between the holes and electrons injected into the organicelectroluminescent element, a charge transporting material other thanthe charge transporting polyester may be dispersed in an amount of 10%by mass to 50% by mass.

As the charge transporting material, in the case of regulating theelectron mobility, examples of the electron transporting materialinclude an oxadiazole derivative, a nitro-substituted fluorenonederivative, a diphenoquinone derivative, a thiopyran dioxide derivative,and a fluorenylidenemethane derivative.

In the case of the layer configurations of the organicelectroluminescent element shown in FIG. 1 to FIG. 4, the back surfaceelectrode 7 uses a metal, a metal oxide, a metal fluoride or the like,which all have a small work function in order to be vacuum deposited andperform electron injection. Examples of the metal include magnesium,aluminum, gold, silver, indium, lithium, calcium, and alloys thereof.Examples of the metal oxide include lithium oxide, magnesium oxide,aluminum oxide, indium tin oxide, tin oxide, indium oxide, zinc oxide,and indium zinc oxide. Furthermore, examples of the metal fluorideinclude lithium fluoride, magnesium fluoride, strontium fluoride,calcium fluoride, and aluminum fluoride.

Furthermore, a protective layer may be further provided on the backsurface electrode 7 in order to prevent deterioration of the element dueto moisture or oxygen. Specific examples of the material for theprotective layer include metals such as In, Sn, Pb, Au, Cu, Ag and Al;metal oxides such as MgO, SiO₂, and TiO₂; and resins such as apolyethylene resin, a polyurea resin, and a polyimide resin. In theformation of the protective layer, a vacuum deposition method, asputtering method, a plasma polymerization method, a CVD method, or acoating method is applied.

These organic electroluminescent elements shown in these FIG. 1 to FIG.4 are produced by first sequentially forming individual layers inaccordance with each of the layer configurations of the organicelectroluminescent element on a transparent electrode 2. The at leastone layer 3 of the hole transport layer and the hole injection layer,the light emitting layer 4, the at least one layer 5 of the electrontransport layer and the electron injection layer, and the light emittinglayer 6 having charge transport capability are formed on a transparentelectrode by a vacuum deposition method, or by dissolving or dispersingthe respective materials in an appropriate organic solvent, and usingthe resulting coating liquid by a spin coating method, a casting method,a dipping method, an inkjet method or the like.

The thicknesses of the at least one layer 3 of the hole transport layerand the hole injection layer, the light emitting layer 4, the at leastone layer 5 of the electron transport layer and the electron injectionlayer, and the light emitting layer 6 having charge transport capabilitymay be respectively 10 μm or less, and particularly in the range of from0.001 μm to 5 μm. The dispersed state of the respective materials (theabove-described non-conjugated polymer, light emitting material, and thelike) may be a molecular dispersed state or may be a particulate statesuch as microcrystals. In the case of a film-forming method using acoating liquid, in order to obtain a molecular dispersed state, it isnecessary to select the dispersion solvent in consideration of thedispersibility and solubility of the respective materials. In order todisperse the materials in a particulate form, a ball mill, a sand mill,a paint shaker, an attriter, a homogenizer, an ultrasonic method or thelike is used.

Finally, in the case of the organic electroluminescent elements shown inFIG. 1 and FIG. 2, the organic electroluminescent element of theexemplary embodiment of the present invention may be obtained by formingthe back surface electrode 7 on the at least one layer 5 of the electrontransport layer and the electron injection layer by a vacuum depositionmethod, a sputtering method or the like. Furthermore, in the case of theorganic electroluminescent element shown in FIG. 3, the organicelectroluminescent element of the exemplary embodiment of the presentinvention may be obtained by forming the back surface electrode 7 on thelight emitting layer 4, and in the case of the organicelectroluminescent element shown in FIG. 4, on the light emitting layer6 having charge transport capability, by a vacuum deposition method, asputtering method or the like.

<Display Medium>

The display medium of the exemplary embodiment of the present inventionis characterized in that the organic electroluminescent element of theexemplary embodiment of the present invention is arranged in at leastone of a matrix form and a segment form. In the case of arranging theorganic electroluminescent element in a matrix form in the exemplaryembodiment, only the electrodes may be arranged in the matrix form, orboth the electrodes and the organic compound layer may be arranged inthe matrix form. Furthermore, in the case of arranging the organicelectroluminescent element in a segment form in the exemplaryembodiment, only the electrodes may be arranged in the segment form, orboth the electrodes and the organic compound layer may be arranged inthe segment form.

The organic compound layer in the matrix form or the segment form iseasily formed by, for example, using the inkjet method described above.

As the driving apparatus for a display medium constituted of the organicelectroluminescent element arranged in a matrix form and the organicelectroluminescent element arranged in the segment form, and the methodfor driving the driving apparatus, the conventionally known ones areused.

EXAMPLES

Hereinafter, the present invention will be described more specificallywith Examples. However, the present invention is not intended to belimited to these Examples.

<Synthesis of Charge Transporting Polyester>

Synthesis Example 1 Synthesis of Exemplary Compound (10)

Acetanilide (25.0 g), methyl 4-iodophenylpropionate (64.4 g), potassiumcarbonate (38.3 g), copper sulfate pentahydrate (2.3 g), and n-tridecane(50 ml) are introduced into a 500-ml three-necked flask, and the mixtureis heated and stirred at 230° C. for 20 hours under a nitrogen gasstream.

After completion of the reaction, potassium hydroxide (15.6 g) dissolvedin ethylene glycol (300 ml) is added thereto, and the resulting mixtureis heated to reflux for 3.5 hours under a nitrogen gas stream, and thenis cooled to room temperature (25° C.). The reaction liquid is pouredinto 1 L of distilled water and neutralized with hydrochloric acid, andcrystals are precipitated out. The crystals are filtered by suctionfiltration, and washed with water, and then the crystals are transferredto a 1-L flask. Toluene (500 ml) is added to this, and the mixture isheated to reflux. Water is removed by azeotropically boiling thereaction mixture, subsequently a methanol (300 ml) solution ofconcentrated sulfuric acid (1.5 ml) is added thereto, and the resultingmixture is heated to reflux for 5 hours under a nitrogen gas stream.

After the reaction, extraction is carried out with toluene, and theorganic layer is washed with pure water. Subsequently, the organic layeris dried over anhydrous sodium sulfate, the solvent is distilled offunder reduced pressure, and recrystallization from hexane is carriedout. Thus, 36.5 g of DAA-1 shown below is obtained.

Subsequently, a liquid mixture of 1-bromo-4-iodobenzene (5.3 g), DAA-1(5.0 g), copper (II) sulfate pentahydrate (0.2 g), potassium carbonate(1.3 g), and tridecane (10 ml) is stirred for 6 hours at 210° C.

After completion of the reaction, potassium hydroxide (15.6 g) dissolvedin ethylene glycol (300 ml) is added to the liquid mixture, and theresulting mixture is heated to reflux for 3.5 hours under a nitrogen gasstream, and then is cooled to room temperature (25° C.). The reactionliquid is poured into 1 L of distilled water and neutralized withhydrochloric acid, and crystals are precipitated out. The crystals arefiltered by suction filtration, and washed with water, and then thecrystals are transferred to a 1-L flask. Toluene (500 ml) is added tothis, and the mixture is heated to reflux. Water is removed byazeotropically boiling the reaction mixture, subsequently a methanol(300 ml) solution of concentrated sulfuric acid (1.5 ml) is addedthereto, and the resulting mixture is heated to reflux for 5 hours undera nitrogen gas stream.

The reaction mixture is cooled to room temperature (25° C.), toluene isadded thereto, and the mixture is filtered through Celite. The filtrateis washed with pure water, and the organic layer is extracted. A productobtained by distilling off the organic solvent of the organic layer isseparated by silica gel column chromatography (hexane 4:toluene 1), andthus 4.5 g of TAA-1 is obtained.

Subsequently, in a 500-ml three-necked flask, a 30% aqueous solution ofhydrogen peroxide (34.0 g) is added dropwise to a mixture ofdibenzothiophene (18.4 g) and acetic acid (200 ml) over 20 minutes, andthe resulting mixture is magnetically stirred for 9 hours at 90° C.

After completion of the reaction, the reaction mixture is introducedinto an ice bath (600 ml), and extraction is carried out with chloroform(800 ml). The organic layer is washed sequentially with water (200 ml),a saturated aqueous solution of iron sulfate (80 ml), 10% sodiumcarbonate (100 ml), water (200 ml), and saturated brine (200 ml), and isdried over calcium chloride. The organic solvent is distilled off, andcolorless crystals are obtained. These crystals are recrystallized (150ml of chloroform, and 200 ml of ethanol), and thus 18.2 g ofdibenzothiophene dioxide is obtained.

In a 500-ml three-necked flask, dibenzothiophene dioxide (18 g) isdissolved in sulfuric acid (250 ml), and N-bromosuccinimide (29.6 g) isadded thereto. The mixture is stirred for 18 hours at room temperature(25° C.), and then the reaction solution is slowly introduced into icewater (800 ml). A precipitate deposited is suction filtered, washed withwater (200 ml), a 10% aqueous solution of NaOH (100 ml) and water (200ml), and dried over calcium chloride. The product is recrystallized fromchloroform (700 ml), and thus 20.1 g of 3,7-dibromodibenzothiophenedioxide is obtained.

Lithium aluminum hydride (4.1 g) is slowly introduced in small amountsover 50 minutes, in an ice bath, into a mixture of3,7-dibromodibenzothiophene dioxide (20 g) and anhydrous ether (200 ml)in a 500-ml flask, and the mixture is heated to reflux and stirred for 2hours. Water (200 ml) is added thereto to deactivate lithium aluminumhydride, and chloroform (200 ml) and concentrated hydrochloric acid (40ml) are added to the mixture. The resulting mixture is thoroughlystirred, and the organic layer is separated. The aqueous layer isfurther extracted with chloroform (200 ml×2), and the extract iscombined with the organic layer. The combined organic layer is washedwith water (200 ml) and saturated brine (200 ml), and is dried overcalcium chloride. The solvent is distilled off, and colorless crystalsthus obtained are recrystallized from ethyl acetate+ethanol (16:3).Thus, 8.8 g of 3,7-dibromodibenzothiophene is obtained.

Under a nitrogen atmosphere, 3,7-dibromodibenzothiophene (8 g) isintroduced into a 500-ml flask, and anhydrous tetrahydrofuran (200 ml)is added thereto to dissolve the compound. The solution is cooled to−78° C. 1.5 M tert-butyllithium (37.8 ml) is slowly added dropwisethereto over 20 minutes, and the mixture is magnetically stirred for 6hours at −78° C. Triisopropyl borate (31.2 ml) is introduced into themixture all at one time, and the resulting mixture is magneticallystirred for 0.5 hour at −78° C. and is further magnetically stirred forone hour at room temperature (25° C.) The mixture is cooled to −78° C.,and 1 M hydrochloric acid (100 ml) is introduced thereto all at onetime. Thereafter, the mixture is magnetically stirred for one hour atroom temperature (25° C.). Tetrahydrofuran is distilled off, and aprecipitate deposited therein is suction filtered and dissolved in a 5%aqueous KOH solution (100 ml). 1 M hydrochloric acid is added to thissolution, and a precipitate deposited therein is suction filtered. Thisprecipitate is dissolved in tetrahydrofuran (300 ml), and2,2-dimethyl-1,3-propanediol (4.5 g), sodium sulfate, and a molecularsieve powder are added to the solution to dry the solution. The solventis distilled off, and colorless crystals thus obtained arerecrystallized from hexane+ethyl acetate. Thus, 4.9 g of a diboronicacid compound is obtained.

Under a nitrogen atmosphere, tetrahydrofuran (250 ml) is added totetra(triphenylphosphine)palladium (0.54 g) and TAA-1 (8.1 g) in a500-ml flask, and the mixture is stirred for 10 minutes. Subsequently, a2 N aqueous solution of sodium carbonate (24.5 ml) and the diboronicacid compound (2.00 g) are added to the mixture, and the resultingmixture is heated to reflux and magnetically stirred for 7 hours.

After completion of the reaction, ethyl acetate (100 ml) and water (50ml) are added to the reaction mixture, and the mixture is thoroughlystirred. Thus, an organic layer and an aqueous layer are separated. Theaqueous layer is extracted with ethyl acetate (100 ml), and therespective organic layers are washed with saturated brine (100 ml) anddried over sodium sulfate. The dried product is subjected to separationby silica gel column chromatography (ethyl acetate/hexane=1/3), andthus, 1.2 g of a monomer compound (6) is obtained.

1.0 g of the monomer compound (6) thus obtained, 10 ml of ethyleneglycol and 0.02 g of tetrabutoxytitanium are introduced into a 50-mlthree-necked pear-shaped flask, and the mixture is heated and stirred at200° C. for 5 hours in a nitrogen atmosphere.

It is confirmed by TLC that the raw material monomer compound (6) hasreacted and disappeared, and then, while ethylene glycol is distilledoff under reduced pressure at 50 Pa, the reaction mixture is heated to210° C. and is allowed to react continuously for 6 hours.

Thereafter, the reaction mixture is cooled to room temperature (25° C.)and is dissolved in 50 ml of tetrahydrofuran The insoluble matter isfiltered through a 0.5-μm polytetrafluoroethylene (PTFE) filter, and thefiltrate is distilled off under reduced pressure. The residue isdissolved in 300 ml of monochlorobenzene, and the solution is washedwith 300 ml of 1 N-HCl and 500 ml×3 of water in this order. Themonochlorobenzene solution is distilled off under reduced pressure to afinal volume of 30 ml, and the concentrated solution is added dropwiseto 800 ml of ethyl acetate/methanol=1/3 to reprecipitate the polymer.The polymer thus obtained is filtered, washed with methanol, and thendried in a vacuum at 60° C. for 16 hours. Thus, 0.6 g of the polymer[Exemplary Compound (10)] is obtained.

The molecular weight of this polymer is measured by gel permeationchromatography (GPC) (manufactured by Tosoh Corp., HLC-8120 GPC), andthe weight average molecular weight is Mw=6.7×10⁴ (relative to styrenestandards), Mw/Mn=2.2, and the degree of polymerization p determinedfrom the molecular weight of the monomer is about 80.

Synthesis Example 2 Synthesis of Exemplary Compound (12)

4-Methylacetanilide (21.0 g), methyl 4-iodophenylpropionate (64.4 g),potassium carbonate (38.3 g), copper sulfate pentahydrate (2.3 g), andtridecane (50 ml) are introduced into a 500-ml three-necked flask, andthe mixture is heated and stirred at 230° C. for 15 hours under anitrogen gas stream.

After completion of the reaction, potassium hydroxide (15.6 g) dissolvedin ethylene glycol (300 ml) is added thereto, and the resulting mixtureis heated to reflux for 3.5 hours under a nitrogen gas stream and thencooled to room temperature (25° C.). The reaction liquid is poured into1 L of distilled water and neutralized with hydrochloric acid, andcrystals are precipitated out. The crystals are filtered by suctionfiltration, and washed with water, and then the crystals are transferredto a 1-L flask. Toluene (500 ml) is added to this, and the mixture isheated to reflux. Water is removed by azeotropically boiling thereaction mixture, subsequently a methanol (300 ml) solution ofconcentrated sulfuric acid (1.5 ml) is added thereto, and the resultingmixture is heated to reflux for 5 hours under a nitrogen gas stream.

After the reaction, extraction is carried out with toluene, and theorganic layer is washed with pure water. Subsequently, the organic layeris dried over anhydrous sodium sulfate, subsequently the solvent isdistilled off under reduced pressure, and recrystallization from hexaneis carried out. Thus, 34.1 g of DAA-2 shown below is obtained.

Subsequently, a liquid mixture of 1-bromo-4-iodobenzene (15.8 g), DAA-2(15.0 g), copper(II) sulfate pentahydrate (0.7 g), potassium carbonate(3.9 g), and tridecane (10 ml) is stirred for 12 hours at 210° C.

After completion of the reaction, potassium hydroxide (15.6 g) dissolvedin ethylene glycol (300 ml) is added to the liquid mixture, and theresulting mixture is heated to reflux for 3.5 hours under a nitrogen gasstream, and then is cooled to room temperature (25° C.). The reactionliquid is poured into 1 L of distilled water and neutralized withhydrochloric acid, and crystals are precipitated out. The crystals arefiltered by suction filtration, and washed with water, and then thecrystals are transferred to a 1-L flask. Toluene (500 ml) is added tothis, and the mixture is heated to reflux. Water is removed byazeotropically boiling the reaction mixture, subsequently a methanol(300 ml) solution of concentrated sulfuric acid (1.5 ml) is addedthereto, and the resulting mixture is heated to reflux for 5 hours undera nitrogen gas stream.

The reaction mixture is cooled to room temperature (25° C.), toluene isadded thereto, and the mixture is filtered through Celite. The filtrateis washed with pure water, and the organic layer is extracted. A productobtained by distilling off the organic solvent of the organic layer isseparated by silica gel column chromatography (hexane 4:toluene 1), andthus 9.3 g of TAA-2 is obtained.

In a nitrogen atmosphere, tetrahydrofuran (300 ml) is added totetra(triphenylphosphine)palladium (0.54 g) and TAA-2 (8.5 g) in a500-ml flask, and the mixture is stirred for 10 minutes. Subsequently, a2 M aqueous solution of sodium carbonate (24.5 ml) and the diboronicacid compound (2.00 g) are added to the mixture, and the resultingmixture is heated to reflux and magnetically stirred for 7 hours.

After completion of the reaction, ethyl acetate (100 ml) and water (50ml) are added to the reaction mixture, and the resulting mixture isthoroughly stirred. Thus, an organic layer and an aqueous layer areseparated. The aqueous layer is extracted with ethyl acetate (100 ml),and the respective organic layers are washed with saturated brine (100ml) and dried over sodium sulfate. The organic layer is separated bysilica gel column chromatography (ethyl acetate/hexane=1/3), and thus1.1 g of a monomer compound (7) is obtained.

1.0 g of the monomer compound (7) thus obtained, 10 ml of ethyleneglycol and 0.02 g of tetrabutoxytitanium are introduced into a 50-mlthree-necked pear-shaped flask, and the mixture is heated and stirredfor 5 hours at 200° C. in a nitrogen atmosphere.

It is confirmed by TLC that the monomer compound (7), which is a rawmaterial, has reacted and disappeared, and then, while ethylene glycolis distilled off under reduced pressure at 50 Pa, the system is heatedto 210° C. and is allowed to react continuously for 6 hours.

Thereafter, the reaction mixture is cooled to room temperature (25° C.)and is dissolved in 50 ml of tetrahydrofuran. The insoluble matter isfiltered through a 0.5-μm polytetrafluoroethylene (PTFE) filter, and thefiltrate is distilled off under reduced pressure. The residue isdissolved in 300 ml of monochlorobenzene, and the solution is washedwith 300 ml of 1 N-HCl and 500 ml×3 of water in this order. Themonochlorobenzene solution is distilled off under reduced pressure to afinal volume of 30 ml, and the concentrated solution is added dropwiseto 800 ml of ethyl acetate/methanol=1/3 to reprecipitate the polymer.The polymer thus obtained is filtered, washed with methanol, and thendried in a vacuum at 60° C. for 16 hours. Thus, 0.7 g of the polymer[Exemplary Compound (12)] is obtained.

The molecular weight of this polymer is measured by gel permeationchromatography (GPC) (manufactured by Tosoh Corp., HLC-8120 GPC), andthe weight average molecular weight is Mw=5.8×10⁴ (relative to styrenestandards), Mw/Mn=2.3, and the degree of polymerization p determinedfrom the molecular weight of the monomer is about 67.

Synthesis Example 3 Synthesis of Exemplary Compound (20)

1-Acetamidonaphthalene (25.0 g), methyl 4-iodophenylpropionate (64.4 g),potassium carbonate (38.3 g), copper sulfate pentahydrate (2.3 g), andtridecane (50 ml) are introduced into a 500-ml three-necked flask, andthe mixture is heated and stirred at 230° C. for 18 hours under anitrogen gas stream.

After completion of the reaction, potassium hydroxide (15.6 g) dissolvedin ethylene glycol (300 ml) is added thereto, and the resulting mixtureis heated to reflux for 3.5 hours under a nitrogen gas stream and thencooled to room temperature (25° C.). The reaction liquid is poured into1 L of distilled water and neutralized with hydrochloric acid, andcrystals are precipitated out. The crystals are filtered by suctionfiltration, and washed with water, and then the crystals are transferredto a 1-L flask. Toluene (500 ml) is added to this, and the mixture isheated to reflux. Water is removed by azeotropically boiling thereaction mixture, subsequently a methanol (300 ml) solution ofconcentrated sulfuric acid (1.5 ml) is added thereto, and the resultingmixture is heated to reflux for 5 hours under a nitrogen gas stream.

After the reaction, extraction is carried out with toluene, and theorganic layer is washed with pure water. Subsequently, the organic layeris dried over anhydrous sodium sulfate, subsequently the solvent isdistilled off under reduced pressure, and recrystallization from hexaneis carried out. Thus, 36.5 g of DAA-3 is obtained.

Subsequently, a liquid mixture of 1-bromo-4-iodobenzene (21.2 g), DAA-3(20 g), copper(II) sulfate pentahydrate (1.0 g), potassium carbonate(5.0 g) and tridecane (12 ml) is stirred for 14 hours at 210° C.

After completion of the reaction, potassium hydroxide (15.6 g) dissolvedin ethylene glycol (300 ml) is added to the reaction mixture, and theresulting mixture is heated to reflux for 3.5 hours under a nitrogen gasstream and then cooled to room temperature (25° C.). The reaction liquidis poured into 1 L of distilled water and neutralized with hydrochloricacid, and crystals are precipitated out. The crystals are filtered bysuction filtration, and washed with water, and then the crystals aretransferred to a 1-L, flask. Toluene (500 ml) is added to this, and themixture is heated to reflux. Water is removed by azeotropically boilingthe reaction mixture, subsequently a methanol (300 ml) solution ofconcentrated sulfuric acid (1.5 ml) is added thereto, and the resultingmixture is heated to reflux for 5 hours under a nitrogen gas stream.

The reaction mixture is cooled to room temperature (25° C.), toluene isadded thereto, and the mixture is filtered through Celite. The filtrateis washed with pure water, and the organic layer is extracted. Theorganic solvent is distilled off, and the product thus obtained isseparated by silica gel column chromatography (hexane 4:toluene 1).Thus, 14.5 g of TAA-3 is obtained.

In a nitrogen atmosphere, tetrahydrofuran (300 ml) is added totetra(triphenylphosphine)palladium (0.537 g) and TAA-3 (8.8 g) in a500-ml flask, and the mixture is stirred for 8 minutes. Subsequently, a2 M aqueous solution of sodium carbonate (24.5 ml) and diboroniccompound 11 (2.00 g) are added thereto, and the mixture is heated toreflux and magnetically stirred for 7 hours.

After completion of the reaction, ethyl acetate (100 ml) and water (50ml) are added to the reaction mixture, and the resulting mixture isthoroughly stirred. Thus, an organic layer and an aqueous layer areseparated. The aqueous layer is extracted with ethyl acetate (100 ml),and the respective organic layers are washed with saturated brine (100ml) and dried over sodium sulfate. The organic layer is separated bysilica gel column chromatography (ethyl acetate/hexane=1/3), and thus1.4 g of a monomer compound (17) is obtained.

1.0 g of the monomer compound (17) thus obtained, 10 ml of ethyleneglycol and 0.02 g of tetrabutoxytitanium are introduced into a 50-mlthree-necked pear-shaped flask, and the mixture is heated and stirredfor 5 hours at 200° C. in a nitrogen atmosphere.

It is confirmed by TLC that the monomer compound (17), which is a rawmaterial, has reacted and disappeared, and then, while ethylene glycolis distilled off under reduced pressure at 50 Pa, the system is heatedto 210° C. and is allowed to react continuously for 6 hours.

Thereafter, the reaction mixture is cooled to room temperature (25° C.)and is dissolved in 50 ml of tetrahydrofuran. The insoluble matter isfiltered through a 0.5-μm polytetrafluoroethylene (PTFE) filter, and thefiltrate is distilled off under reduced pressure. The residue isdissolved in 300 ml of monochlorobenzene, and the solution is washedwith 300 ml of 1 N-HCl and 500 ml×3 of water in this order. Themonochlorobenzene solution is distilled off under reduced pressure to afinal volume of 30 ml, and the concentrated solution is added dropwiseto 800 ml of ethyl acetate/methanol=1/3 to reprecipitate the polymer.The polymer thus obtained is filtered, washed with methanol, and thendried in a vacuum at 60° C. for 16 hours. Thus, 0.6 g of the polymer[Exemplary Compound (20)] is obtained.

The molecular weight of this polymer is measured by gel permeationchromatography (GPC) (manufactured by Tosoh Corp., HLC-8120 GPC), andthe weight average molecular weight is Mw=5.3×10⁴ (relative to styrenestandards), Mw/Mn=2.4, and the degree of polymerization p determinedfrom the molecular weight of the monomer is about 57.

Synthesis Example 4 Synthesis of Exemplary Compound (22)

4-(2-Thienyl)acetanilide (30.0 g), methyl. 4-iodophenylpropionate (28.5g), potassium carbonate (13.6 g), copper sulfate pentahydrate (2.0 g),and 1,2-dichlorobenzene (50 ml) are introduced into a 500-mlthree-necked flask, and the mixture is heated and stirred at 230° C. for12 hours under a nitrogen gas stream.

After completion of the reaction, potassium hydroxide (15.6 g) dissolvedin ethylene glycol (300 ml) is added thereto, and the resulting mixtureis heated to reflux for 3.5 hours under a nitrogen gas stream and thencooled to room temperature (25° C.). The reaction liquid is poured into1 L of distilled water and neutralized with hydrochloric acid, andcrystals are precipitated out. The crystals are filtered by suctionfiltration, and washed with water, and then the crystals are transferredto a 1-L flask. Toluene (500 ml) is added to this, and the mixture isheated to reflux. Water is removed by azeotropically boiling thereaction mixture, subsequently a methanol (300 ml) solution ofconcentrated sulfuric acid (1.5 ml) is added thereto, and the resultingmixture is heated to reflux for 5 hours under a nitrogen gas stream.

After the reaction, extraction is carried out with toluene, and theorganic layer is washed with pure water. Subsequently, the organic layeris dried over anhydrous sodium sulfate, subsequently the solvent isdistilled off under reduced pressure, and recrystallization from hexaneis carried out. Thus, 17.9 g of DAA-4 is obtained.

In a nitrogen atmosphere, a liquid mixture of 1-bromo-4-iodobenzene(15.9 g), DAA-4 (16.0 g), copper (II) sulfate pentahydrate (0.2 g),potassium carbonate (1.3 g) and tridecane (15 ml) is stirred for 15hours at 210° C.

After completion of the reaction, potassium hydroxide (15.6 g) dissolvedin ethylene glycol (300 ml) is added thereto, and the resulting mixtureis heated to reflux for 3.5 hours under a nitrogen gas stream and thencooled to room temperature (25° C.). The reaction liquid is poured into1 L of distilled water and neutralized with hydrochloric acid, andcrystals are precipitated out. The crystals are filtered by suctionfiltration, and washed with water, and then the crystals are transferredto a 1-L flask. Toluene (500 ml) is added to this, and the mixture isheated to reflux. Water is removed by azeotropically boiling thereaction mixture, subsequently a methanol (300 ml) solution ofconcentrated sulfuric acid (1.5 ml) is added thereto, and the resultingmixture is heated to reflux for 5 hours under a nitrogen gas stream.

After cooling, toluene is added to the reaction mixture, and the mixtureis filtered through Celite. Toluene is distilled off, and the productthus obtained is separated by silica gel column chromatography (hexane2:toluene 1). Thus, 9.1 g of TAA-4 is obtained.

In a nitrogen atmosphere, tetrahydrofuran (250 ml) is added totetra(triphenylphosphine)palladium (0.54 g) and TAA-4 (8.6 g) in a500-ml flask, and the mixture is stirred for 10 minutes. Subsequently, a2 M aqueous solution of sodium carbonate (24.5 ml) and the diboronicacid compound (2.00 g) are added to the mixture, and the resultingmixture is heated to reflux and magnetically stirred for 7 hours.

After completion of the reaction, ethyl acetate (100 ml) and water (50ml) are added to the reaction mixture, and the mixture is thoroughlystirred. Thus, an organic layer and an aqueous layer are separated. Theaqueous layer is extracted with ethyl acetate (100 ml), and therespective organic layers are washed with saturated brine (100 ml), anddried over sodium sulfate. The dried product is separated by silica gelcolumn chromatography (ethyl acetate/hexane=1/3), and thus 1.2 g of amonomer compound (19) is obtained.

1.0 g of the monomer compound (19) thus obtained, 10 ml of ethyleneglycol and 0.02 g of tetrabutoxytitanium are introduced into a 50-mlthree-necked pear-shaped flask, and the mixture is heated and stirredfor 5 hours at 200° C. in a nitrogen atmosphere.

It is confirmed by TLC that the raw material monomer compound (19) hasreacted and disappeared, and then, while ethylene glycol is distilledoff under reduced pressure at 50 Pa, the reaction mixture is heated to210° C. and is allowed to react continuously for 6 hours.

Thereafter, the reaction mixture is cooled to room temperature (25° C.)and is dissolved in 50 ml of tetrahydrofuran. The insoluble matter isfiltered through a 0.5-μm polytetrafluoroethylene (PTFE) filter, and thefiltrate is distilled off under reduced pressure. The residue isdissolved in 300 ml of monochlorobenzene, and the solution is washedwith 300 ml of 1 N-HCl and 500 ml×3 of water in this order. Themonochlorobenzene solution is distilled off under reduced pressure to afinal volume of 30 ml, and the concentrated solution is added dropwiseto 800 ml of ethyl acetate/methanol=1/3 to reprecipitate the polymer.The polymer thus obtained is filtered, washed with methanol, and thendried in a vacuum at 60° C. for 16 hours. Thus, 0.6 g of the polymer[Exemplary Compound (22)] is obtained.

The molecular weight of this polymer is measured by gel permeationchromatography (GPC) (manufactured by Tosoh Corp., HLC-8120 GPC), andthe weight average molecular weight is Mw=6.8×10⁴ (relative to styrenestandards), Mw/Mn=2.1, and the degree of polymerization p determinedfrom the molecular weight of the monomer is about 68.

Synthesis Example 5 Synthesis of Exemplary Compound (23)

In a nitrogen atmosphere, 2-iodo-9,9-dimethylfluorene (31.8 g), methyl4-acetaminophenylpropionate (20.0 g), potassium carbonate (18.8 g),copper sulfate pentahydrate (1.2 g), and tridecane (15 ml) areintroduced into a 300-ml three-necked flask, and the mixture is heatedand stirred at 200° C. for 13 hours under a nitrogen gas stream.

After completion of the reaction, ethylene glycol (150 ml) and potassiumhydroxide (7.6 g) are added thereto, and the resulting mixture is heatedto reflux for 5 hours under a nitrogen gas stream and then cooled toroom temperature (25° C.). The cooled product is poured into 150 ml ofdistilled water and neutralized with hydrochloric acid, and crystals areprecipitated out. These crystals are filtered and washed with water, andthen the crystals are transferred to a 500-ml flask. Toluene (500 ml) isadded to this, and the mixture is heated to reflux. Water is removed byazeotropically boiling the reaction mixture, subsequently methanol (100ml) and concentrated sulfuric acid (1.0 ml) are added thereto, and theresulting mixture is heated to reflux for 5 hours under a nitrogen gasstream.

After the reaction, extraction is carried out with toluene, and theorganic layer is washed with distilled water. Subsequently, the organiclayer is dried over anhydrous sodium sulfate, subsequently the solventis distilled off under reduced pressure, and recrystallization fromhexane is carried out. Thus, 25 g of DAA-5 is obtained.

Subsequently, a liquid mixture of 1-bromo-4-iodobenzene (21.2 g), DAA-5(20 g), copper (II) sulfate pentahydrate (1.0 g), potassium carbonate(4.5 g) and tridecane (10 ml) is stirred for 8 hours at 210° C.

After completion of the reaction, ethylene glycol (150 ml) and potassiumhydroxide (7.6 g) are added thereto, and the resulting mixture is heatedto reflux for 5 hours under a nitrogen gas stream and then cooled toroom temperature (25° C.). The cooled product is poured into 150 ml ofdistilled water and neutralized with hydrochloric acid, and crystals areprecipitated out. These crystals are filtered and washed with water, andthen the crystals are transferred to a 500-ml flask. Toluene (500 ml) isadded to this, and the mixture is heated to reflux. Water is removed byazeotropically boiling the reaction mixture, subsequently methanol (100ml) and concentrated sulfuric acid (1.0 ml) are added thereto, and theresulting mixture is heated to reflux for 5 hours under a nitrogen gasstream.

The reaction mixture is cooled to room temperature (25° C.), toluene isadded thereto, and the mixture is filtered through Celite. The filtrateis washed with pure water, and the organic layer is extracted. Theorganic solvent is distilled off, and a product thus obtained isseparated by silica gel column chromatography (hexane 4:toluene 1).Thus, 15.6 g of TAA-5 is obtained.

In a nitrogen atmosphere, tetrahydrofuran (250 ml) is added totetra(triphenylphosphine)palladium (0.54 g) and TAA-5 (8.8 g) in a500-ml flask, and the mixture is stirred for 10 minutes. Subsequently, a2 M aqueous solution of sodium carbonate (24.5 ml) and the diboronicacid compound (2.00 g) are added to the mixture, and the resultingmixture is heated to reflux and magnetically stirred for 7 hours.

After completion of the reaction, ethyl acetate (100 ml) and water (50ml) are added to the reaction mixture, and the mixture is thoroughlystirred. Thus, an organic layer and an aqueous layer are separated. Theaqueous layer is extracted with ethyl acetate (100 ml), and therespective organic layers are washed with saturated brine (100 ml), anddried over sodium sulfate. The dried product is separated by silica gelcolumn chromatography (ethyl acetate/hexane=1/3), and thus 1.2 g of amonomer compound (23) is obtained.

1.0 g of the monomer compound (23) thus obtained, 10 ml of ethyleneglycol and 0.02 g of tetrabutoxytitanium are introduced into a 50-mlthree-necked pear-shaped flask, and the mixture is heated and stirredfor 5 hours at 200° C. in a nitrogen atmosphere.

It is confirmed by TLC that the raw material monomer compound (23) hasreacted and disappeared, and then, while ethylene glycol is distilledoff under reduced pressure at 50 Pa, the reaction mixture is heated to210° C. and is allowed to react continuously for 6 hours.

Thereafter, the reaction mixture is cooled to room temperature (25° C.)and is dissolved in 50 ml of tetrahydrofuran. The insoluble matter isfiltered through a 0.5-μm polytetrafluoroethylene (PTFE) filter, and thefiltrate is distilled off under reduced pressure. The residue isdissolved in 300 ml of monochlorobenzene, and the solution is washedwith 300 ml of 1 N-HCl and 500 ml×3 of water in this order. Themonochlorobenzene solution is distilled off under reduced pressure to afinal volume of 30 ml, and the concentrated solution is added dropwiseto 800 ml of ethyl acetate/methanol=1/3 to reprecipitate the polymer.The polymer thus obtained is filtered, washed with methanol, and thendried in a vacuum at 60° C. for 16 hours. Thus, 0.6 g of the polymer[Exemplary Compound (23)] is obtained.

The molecular weight of this polymer is measured by gel permeationchromatography (GPC) (manufactured by Tosoh Corp., HLC-8120 GPC), andthe weight average molecular weight is Mw=8.9×10⁴ (relative to styrenestandards), Mw/Mn=2.4, and the degree of polymerization p determinedfrom the molecular weight of the monomer is about 83.

Synthesis Example 6 Synthesis of Exemplary Compound (18)

In a nitrogen atmosphere, 3-bromobiphenyl (23 g), methyl4-acetaminophenylpropionate (20 g), potassium carbonate (18.8 g), coppersulfate pentahydrate (1.1 g), and tridecane (20 ml) are introduced intoa 300-ml three-necked flask, and the mixture is heated and stirred at200° C. for 24 hours under a nitrogen gas stream.

After completion of this reaction, ethylene glycol (150 ml) andpotassium hydroxide (6.5 g) are added thereto, and the resulting mixtureis heated to reflux for 3 hours under a nitrogen gas stream and thencooled to room temperature (25° C.). The cooled product is poured into150 ml of distilled water and neutralized with hydrochloric acid, andcrystals are precipitated out. These crystals are filtered and washedwith water, and then the crystals are transferred to a 500-ml flask.Toluene (500 ml) is added to this, and the mixture is heated to reflux.Water is removed by azeotropically boiling the reaction mixture,subsequently methanol (100 ml) and concentrated sulfuric acid (1.0 ml)are added thereto, and the resulting mixture is heated to reflux for 5hours under a nitrogen gas stream.

After the reaction, extraction is carried out with toluene, and theorganic layer is washed with distilled water. Subsequently, the organiclayer is dried over anhydrous sodium sulfate, subsequently the solventis distilled off under reduced pressure, and recrystallization fromhexane is carried out. Thus, 25 g of DAA-6 is obtained.

Subsequently, a liquid mixture of 1-bromo-4-iodobenzene (15.9 g), DAA-6(15 g), copper(II) sulfate pentahydrate (0.6 g), potassium carbonate(3.9 g) and tridecane (10 ml) is stirred for 10 hours at 210° C.

After completion of the reaction, ethylene glycol (150 ml) and potassiumhydroxide (6.5 g) are added thereto, and the resulting mixture is heatedto reflux for 3 hours under a nitrogen gas stream and then cooled toroom temperature (25° C.). The cooled product is poured into 150 ml ofdistilled water and neutralized with hydrochloric acid, and crystals areprecipitated out. These crystals are filtered and washed with water, andthen the crystals are transferred to a 500-ml flask. Toluene (500 ml) isadded to this, and the mixture is heated to reflux. Water is removed byazeotropically boiling the reaction mixture, subsequently methanol (100ml) and concentrated sulfuric acid (1.0 ml) are added thereto, and theresulting mixture is heated to reflux for 5 hours under a nitrogen gasstream.

The reaction mixture is cooled to room temperature (25° C.), toluene isadded thereto, and the mixture is filtered through Celite. The filtrateis washed with pure water, and the organic layer is extracted. Theorganic solvent is distilled off, and a product thus obtained isseparated by silica gel column chromatography (hexane 4:toluene 1).Thus, 11.7 g of TAA-6 is obtained.

In a nitrogen atmosphere, tetrahydrofuran (250 ml) is added totetra(triphenylphosphine)palladium (0.54 g) and TAA-6 (8.6 g) in a500-ml flask, and the mixture is stirred for 10 minutes. Subsequently, a2 M aqueous solution of sodium carbonate (24.5 ml) and the diboronicacid compound (2.00 g) are added to the mixture, and the resultingmixture is heated to reflux and magnetically stirred for 7 hours.

After completion of the reaction, ethyl acetate (100 ml) and water (50ml) are added to the reaction mixture, and the mixture is thoroughlystirred. Thus, an organic layer and an aqueous layer are separated. Theaqueous layer is extracted with ethyl acetate (100 ml), and therespective organic layers are washed with saturated brine (100 ml), anddried over sodium sulfate. The dried product is separated by silica gelcolumn chromatography (ethyl acetate/hexane=1/3), and thus 1.2 g of amonomer compound (15) is obtained.

1.0 g of the monomer compound (15) thus obtained, 10 ml of ethyleneglycol and 0.02 g of tetrabutoxytitanium are introduced into a 50-mlthree-necked pear-shaped flask, and the mixture is heated and stirredfor 5 hours at 200° C. in a nitrogen atmosphere.

It is confirmed by TLC that the raw material monomer compound (15) hasreacted and disappeared, and then, while ethylene glycol is distilledoff under reduced pressure at 50 Pa, the reaction mixture is heated to210° C. and is allowed to react continuously for 6 hours.

Thereafter, the reaction mixture is cooled to room temperature (25° C.)and is dissolved in 50 ml of tetrahydrofuran. The insoluble matter isfiltered through a 0.5-μm polytetrafluoroethylene (PTFE) filter, and thefiltrate is distilled off under reduced pressure. The residue isdissolved in 300 ml of monochlorobenzene, and the solution is washedwith 300 ml of 1 N-HCl and 500 ml×3 of water in this order. Themonochlorobenzene solution is distilled off under reduced pressure to afinal volume of 30 ml, and the concentrated solution is added dropwiseto 800 ml of ethyl acetate/methanol=1/3 to reprecipitate the polymer.The polymer thus obtained is filtered, washed with methanol, and thendried in a vacuum at 60° C. for 16 hours. Thus, 0.6 g of the polymer[Exemplary Compound (18)] is obtained.

The molecular weight of this polymer is measured by gel permeationchromatography (GPC) (manufactured by Tosoh Corp., HLC-8120 GPC), andthe weight average molecular weight is Mw=4.9×10⁴ (relative to styrenestandards), Mw/Mn=2.2, and the degree of polymerization p determinedfrom the molecular weight of the monomer is about 49.

Example 1

ITO (manufactured by Sanyo Vacuum Industries Co., Ltd.) formed on atransparent insulating substrate is subjected to patterning byphotolithography using a strip-shaped photomask, and the ITO is furthersubjected to an etching treatment. Thereby, a strip-shaped ITO electrode(width 2 mm) is formed. Subsequently, this ITO glass substrate is washedwith a neutral detergent, ultrapure water, acetone (electronic grade,manufactured by Kanto Chemical Co., Inc.) and isopropanol (electronicgrade, manufactured by Kanto Chemical Co., Inc.) while applyingultrasonic waves for 5 minutes for each, and then the ITO glasssubstrate is dried with a spin coater.

A 5% by mass monochlorobenzene solution of the charge transportingpolyester [Exemplary Compound (10)] is prepared, the solution isfiltered through a 0.2-μm PTFE filter, and then a thin film having athickness of 0.050 μm of this solution is formed, as a hole transportlayer, on the above-described substrate by a spin coating method. TheExemplary Compound (XV-1) is deposited as a light emitting material, anda light emitting layer having a thickness of 0.055 μm is formed.Subsequently, a metallic mask provided with strip-shaped holes isprovided thereon, and then LiF is deposited to a thickness of 0.0001 μm.Subsequently, Al is deposited to a thickness of 0.150 μm, and then aback surface electrode having a width of 2 mm and a thickness of 0.15 μmis formed so as to intersect with the ITO electrode. The effective areaof the organic electroluminescent element thus formed is 0.04 cm².

Example 2

A 10% by mass dichloroethane solution of 1 part by mass of the chargetransporting polyester [Exemplary Compound (12)], 4 parts by mass ofpoly (N-vinylcarbazole) and 0.02 part by mass of the Exemplary Compound(XV-1) is prepared, and the solution is filtered through a 0.2-μm PTFEfilter. On a glass substrate on which a strip-shaped ITO electrode hasbeen etched, washed and dried in the same manner as in Example 1, a thinfilm having a thickness of 0.15 μm is formed using the above solution bya spin coating method. After the thin film is sufficiently dried, LiF isdeposited to a thickness of 0.0001 μm by installing a metal maskprovided with strip-shaped holes. Subsequently, Al is deposited to athickness of 0.150 μm, and a back surface electrode having a width of 2mm and a thickness of 0.15 μm is formed so as to intersect with the ITOelectrode. The effective area of the organic electroluminescent elementthus formed is 0.04 cm².

Example 3

On an ITO glass substrate which has been etched, washed and dried in thesame manner as in Example 1, a layer having a thickness of 0.050 μm isformed, as a hole transport layer, using the charge transportingpolyester [Exemplary Compound (20)] in the same manner as in Example 1.Subsequently, a mixture of the Exemplary Compound (XV-1) and theExemplary Compound (XVI-1) (mass ratio: 99/1) is used to form a layerhaving a thickness of 0.065 μm as a light emitting layer. As an electrontransport layer, the Exemplary Compound (XV-9) is used to form a layerhaving a thickness of 0.030 μm. After the layers are sufficiently dried,LiF is deposited to a thickness of 0.0001 μm by installing a metal maskprovided with strip-shaped holes. Subsequently, Al is deposited to athickness of 0.150 μm, and a back surface electrode having a width of 2mm and a thickness of 0.15 μm is formed so as to intersect with the ITOelectrode. The effective area of the organic electroluminescent elementthus formed is 0.04 cm².

Example 4

On an ITO glass substrate which has been etched, washed and dried in thesame manner as in Example 1, a layer having a thickness of 0.050 μm isformed, as a hole transport layer, by an inkjet method (a piezoinkjetsystem) using the charge transporting polyester [Exemplary Compound(22)] in the same manner as in Example 1. Subsequently, as a lightemitting layer, a layer of the Exemplary Compound (XV-16, n=8)containing 5% by mass of the Exemplary Compound (XVI-5) is formed to athickness of 0.065 μm by a spin coating method. After the layers aresufficiently dried, Ca is deposited to a thickness of 0.08 μm, Al isdeposited to a thickness of 0.15 μm, and a back surface electrode havinga width of 2 mm and a thickness of 0.23 μm is formed so as to intersectwith the ITO electrode. The effective area of the organicelectroluminescent element thus formed is 0.04 cm².

Example 5

An organic electroluminescent element is produced in the same manner asin Example 2, except that the charge transporting polyester [ExemplaryCompound (23)] is used instead of the charge transporting polyester[Exemplary compound (10)] used in Example 1.

Example 6

An organic electroluminescent element is produced in the same manner asin Example 3, except that the charge transporting polyester [ExemplaryCompound (18)] is used instead of the charge transporting polyester[Exemplary Compound (10)] used in Example 1.

Example 7

A 1.5% by mass dichloroethane solution of a charge transportingpolyester [Exemplary Compound (10)] is prepared, and the solution isfiltered through a 0.2-μm PTFE filter. On an ITO glass substrate whichhas been etched, washed and dried in the same manner as in Example 1, athin film having a thickness of 0.05 μm is formed by an inkjet methodusing the above solution. Subsequently, the Exemplary Compound (XV-16, n8) containing 5% by mass of the Exemplary Compound (XVI-5) is used as alight emitting material to form a light emitting layer to a thickness of0.050 μm by a spin coating method. After the layers are sufficientlydried, Ca is deposited to a thickness of 0.08 μm, Al is deposited to athickness of 0.15 μm, and a back surface electrode having a width of 2mm and a thickness of 0.23 μm is formed so as to intersect with the ITOelectrode. The effective area of the organic electroluminescent elementthus formed is 0.04 cm².

Example 8

On an ITO glass substrate which has been etched, washed and dried in thesame manner as in Example 1, a layer of the Exemplary Compound (XV-16)is formed as a light emitting layer to a thickness of 0.050 μl. A 1.5%by mass dichloroethane solution of the charge transporting polyester[Exemplary Compound (10)] is prepared, and the solution is filteredthrough a 0.2-μm PTFE filter. This solution is used to form an electrontransport layer having a thickness of 0.015 μm formed on the lightemitting layer by a spin coating method. After the layers aresufficiently dried, LiF is deposited to a thickness of 0.0001 μm using ametal mask provided with strip-shaped holes, Al is deposited to athickness of 0.150 μm, and a back surface electrode having a width of 2mm and a thickness of 0.15 μm is formed so as to intersect with the ITOelectrode. The effective area of the organic electroluminescent elementthus formed is 0.04 cm².

Comparative Example 1

An organic EL element is produce in the same manner as in Example 2,except that a compound represented by the following structural formula(XVII) is used instead of the charge transporting polyester [ExemplaryCompound (10)] used in Example 1.

Comparative Example 2

Two parts by mass of polyvinylcarbazole (PVK) as a charge transportingpolymer, 0.1 part by mass of the Exemplary Compound (XV-1) as a lightemitting material, and 1 part by mass of the Exemplary Compound (XV-9)as an electron transporting material are mixed to prepare a 10% by massdichloroethane solution, and the solution is filtered through a 0.2-μmPTFE filter. On a glass substrate on which a strip-shaped ITO electrodehaving a width of 2 mm is formed by etching, a hole transport layerhaving a thickness of 0.15 μm is formed by applying the above solutionby a dipping method. After the layers are sufficiently dried, LiF isdeposited to a thickness of 0.0001 μm using a metal mask provided withstrip-shaped holes, subsequently Al is deposited to a thickness of 0.150μm and a back surface electrode having a width of 2 mm and a thicknessof 0.15 μm is formed so as to intersect with the ITO electrode. Theeffective area of the organic electroluminescent element thus formed is0.04 cm².

Comparative Example 3

Two parts by mass of a compound having a structure represented by thefollowing structural formula (XVIII) as a charge transporting polymer,0.1 part by mass of the Exemplary Compound (XV-1) as a light emittingmaterial, and 1 part by mass of the compound (XV-9) as an electrontransporting material are mixed to prepare a 10% by mass dichloroethanesolution, and the solution is filtered through a 0.1-μm PTFE filter. Ona glass substrate on which a strip-shaped ITO electrode having a widthof 2 mm is formed by etching, a hole transport layer having a thicknessof 0.15 μm is formed by applying the above solution by a dipping method.After the layers are sufficiently dried, LiF is deposited to a thicknessof 0.0001 μm using a metal mask provided with strip-shaped holes,subsequently Al is deposited to a thickness of 0.150 μm, and a backsurface electrode having a width of 2 mm and a thickness of 0.15 μm isformed so as to intersect with the ITO electrode. The effective area ofthe organic electroluminescent element thus formed is 0.04 cm².

Comparative Example 4

An organic EL element is produced in the same manner as in Example 1,except that a compound having a structure represented by the followingstructural formula (XIX) is used instead of the charge transportingpolyester [Exemplary. Compound (10)] used in Example 1.

For the organic EL elements produced as described above, a directcurrent voltage is applied in dry nitrogen by connecting the ITOelectrode side as a positive electrode and the back surface electrode asa negative electrode, and measurements are made.

The evaluation of luminescence lifetime is carried out by setting theinitial luminance to 1000 cd/m² in a direct current driving system (DCdriving) at room temperature (25° C.), and determining the relative timewhen the driving time at the time point at which the luminance of theelement of Comparative Example 1 (initial luminance L₀: 1000 cd/m²)reaches luminance L/initial luminance L₀=0.5, is designated as 1.0, andthe voltage increment (=voltage/initial driving voltage) at the timepoint at which the luminance of the element reaches luminance L/initialluminance L₀=0.5. The results are shown in Table 7.

TABLE 7 Voltage increase Relative time (@L/L₀ = 0.5) (L/L₀ = 0.5)Example 1 1.18 1.75 Example 2 1.12 1.48 Example 3 1.16 1.58 Example 41.15 1.62 Example 5 1.14 1.58 Example 6 1.12 1.49 Example 7 1.11 1.55Example 8 1.15 1.58 Comparative Example 1 1.41 1.00 Comparative Example2 1.26 1.15 Comparative Example 3 1.35 1.20 Comparative Example 4 1.251.32

From the results shown in Table 7, it is understood that in the organicelectroluminescent elements of Examples 1 to 8 using the chargetransporting polyester according to the exemplary embodiment of thepresent invention, an increase in voltage is suppressed, and theluminescence lifetime is better than those using the conventional chargetransporting polymers.

Furthermore, at is understood that in the organic electroluminescentelements according to the exemplary embodiment of the present invention,since the charge transporting polyester exhibits solubility in organicsolvents, large-area organic electroluminescent elements can be easilyproduced.

The foregoing description of the exemplary embodiments of the presentinvention has been provided for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise forms disclosed. Obviously, many modificationsand variations will be apparent to practitioners skilled in the art. Theembodiments were chosen and described in order to best explain theprinciples of the invention and its practical applications, therebyenabling others skilled in the art to understand the invention forvarious embodiments and with the various modifications as are suited tothe particular use contemplated. It is intended that the scope of theinvention be defined by the following claims and their equivalents.

What is claimed is:
 1. An organic electroluminescent element comprising:a pair of electrodes including a positive electrode and a negativeelectrode, with at least one of the electrodes being transparent orsemi-transparent; and one or more organic compound layers interposedbetween the pair of electrodes, with at least one layer containing oneor more charge transporting polyesters represented by the followingformula (I):

wherein in the formula (I), A¹ represents at least one selected fromstructures represented by the following formula (II); Y¹s eachindependently represent a substituted or unsubstituted divalenthydrocarbon group; m's each independently represent an integer of from 1to 5; p represents an integer of from 5 to 5,000; R¹s each independentlyrepresent a hydrogen atom, an alkyl group, a substituted orunsubstituted aryl group, or a substituted or unsubstituted aralkylgroup;

wherein in the formula (II), Ar's each independently represent asubstituted or unsubstituted phenyl group, a substituted orunsubstituted monovalent polynuclear aromatic hydrocarbon group havingtwo aromatic rings, a substituted or unsubstituted monovalent condensedaromatic hydrocarbon group having two or three aromatic rings, or asubstituted or unsubstituted monovalent aromatic heterocyclic group; j'seach independently represent 0 or 1; T's each independently represent adivalent linear hydrocarbon group having from 1 to 6 carbon atoms, or adivalent branched hydrocarbon group having from 2 to 10 carbon atoms;and X represents a group represented by the following formula (III):


2. The organic electroluminescent element of claim 1, wherein theorganic compound layers include a light emitting layer, at least onelayer of a hole transport layer and a hole injection layer, and at leastone layer of an electron transport layer and an electron injectionlayer, and at least one layer selected from the light emitting layer,the hole transport layer, the hole injection layer, the electrontransport layer and the electron injection layer contains one or morecharge transporting polyesters represented by the formula (I).
 3. Theorganic electroluminescent element of claim 1, wherein the organiccompound layers are formed only of a light emitting layer having acharge transport function, and the light emitting layer having a chargetransport function contains one or more charge transporting polyestersrepresented by the formula (I).
 4. A display medium comprising theorganic electroluminescent element of claim 1 arranged in at least oneof a matrix form and a segment form.
 5. The organic electroluminescentelement of claim 1, wherein the organic compound layers include a lightemitting layer and at least one layer of an electron transport layer andan electron injection layer, and at least one layer selected from thelight emitting layer, the electron transport layer and the electroninjection layer contains one or more charge transporting polyestersrepresented by the formula (I).
 6. A display medium comprising theorganic electroluminescent element of claim 5 arranged in at least oneof a matrix form and a segment form.
 7. The organic electroluminescentelement of claim 1, wherein the organic compound layers include a lightemitting layer and at least one layer of a hole transport layer and ahole injection layer, and at least one layer selected from the lightemitting layer, the hole transport layer and the hole injection layercontains one or more charge transporting polyesters represented by theformula (I).
 8. A display medium comprising the organicelectroluminescent element of claim 7 arranged in at least one of amatrix form and a segment form.